Condensed Matter Seminars

In the flurry of experiments looking for topological insulator materials, it has been found that some bulk metals very close to topological insulator electronic states support the same topological surface states that are the defining characteristic of the topological insulator. First observed in spin-polarized angle resolved photoemission spectroscopy (ARPES) in Sb [D. Hsieh et al., Science 323, 919 (2009)], the helical surface states in the metallic systems appear to be robust to at least mild disorder. We present an investigation of the nature of these "topological conductors" - bulk metals with helical surface states. We explore how the surface states can survive the insulator being turned into a metal, in both clean and disordered systems. We also explore magnetoelectric coupling phenomena in these systems, which turn out to realize an analog of the intrinsic anomalous Hall effect.